copy object location to another scene? BGE
I see two options:


You want interaction between two scenes? Pointless. Make one scene.
You want to "augment" the main scene with your overlay and need to place things on top of each other? Do it in screen space, don't do it XYZ or what ever. Simply measure where your desired location is visible on your monitor. Make a global storage to place your result in. Then in the other scene read from there, to place your "augmentation" on the spot.


EDIT:

First: It's quite hard to understand you. My apologies.
But: Have you ever played multiplayer games before? That has to work somehow, doesn't it? Im sure, you need not be afraid of Blender limiting anything across your scenes...

In fact however, talking about limitations, Blenders game engine is really a bad choice. I tested it for myself, you don't even have delta times for your animations. The game engine is simply not an objective for the developers.

With that, I want to draw your attention to render layers. Search them through google, maybe they are just what you wanted.

In relation to your original question, I think you have some issue understanding the situation.

Let me clarify:


Your Scenes are seperate. And they are meant to be!


"cloning" anything in a scene into another scene is pointless, since it conflicts with the purpose of scenes. 

But, of course you can. In this case you need at least the camera vector and/or the desired objects vector to be cloned. Which reveals the problem: Different dimensions.
You can have a Camera over a map moving according to the players location in the main scene. You always must do a translation, even if sizes and locations stay the same. 

I hope this helps.